1. Field of the Invention
The invention relates to a perfusion device for perfusion bags of blood or solution; the pressurization means is portable and automatic, with double pressure balloons, and whose drip is provided with means ensuring its verticality.
The invention permits two types of perfusion. Conventional slow perfusion, with automatic constant pressure or drip and emergency rapid perfusion under high pressure.
The device permits using the two types of perfusion or simultaneously transfusion.
The parenteral perfusion device is portable and automatic, with air pressure adjusted by an expansion valve for one of the balloons.
This autonomous perfuser can be fixed to the subject or to the immediate environs; it operates by closed circuit, it is independent of gravity and atmospheric pressure.
The balloon which is not under regulated air pressure can permit injection, for example of blood, under very high pressure.
The perfusion device also comprises a means to ensure the verticality of the drip, no matter what the position of the perfused subject and/or of the perfuser.
This invention finds application in medical and veterinary fields.
It is a common sight to see a seriously injured person carried on a stretcher or a sick person, receiving perfusion; someone follows the stretcher, carrying at a certain height a pouch of serum or of blood and its perfusion tubing. The solution pouch is situated above the perfused vein to permit gravity flow of the liquid which it contains.
This process has numerous drawbacks which various patents have already attempted to remedy.
2. The State of the Prior Art
Hinck (U.S. Pat. No. 4,090,514 of May 23, 1978) discloses a bladder inflatable by means of a conventional device with a pressure bulb and manometer, used for stretcher cases: the flow of the liquid to be perfused takes place in the usual way dropwise. The Hinck device is adapted to be suspended vertically instead of and in place of a glass bottle adjacent the bed of the patient. Operating by gravity, it serves above all to accelerate the flow: it is not provided to operate in all positions.
The Hinck device comprises but a single pressure bag: it therefore cannot ensure complete regularity of perfusion. Thus, to the extent that the perfusion pouch empties, the pressure of the pressure balloon surrounding the pouch can only decrease, which results in slowing of the speed of flow of the perfused liquid. To overcome this drawback, the operator can either increase the pressure by means of the pressure bulb, or modify the flow rate of the drip, this process is however not automatic and requires continuous surveillance by a third person. In any case, regularity is not ensured and requires human intervention.
The Hinck apparatus does not permit ensuring perfusion over a range of operating pressures, these not being regulable.
Two other patents, Leibinsohn (EP 0 102 012 of Mar. 7, 1984) and Zoratto (EP 0 210 424 of Feb. 4, 1987) include substantially the same elements and do not comprise new inventive elements relative to Hinck.
B. Keime (GB-A-2 165 312 of Apr. 9, 1986) discloses a device with a sealed housing containing the bag of liquid to be perfused, connected to a cartridge of inert gas, by means of an expansion valve. There is a rigid unexpandable housing, therefore equivalent to a device with a single bag, identical in principle to the preceding patents.
The drawbacks connected with the Keime device are as follows:
the use of an inert gas cartridge which gives no clue as to how full it is, PA1 in the absence of a cartridge, this device is useless, PA1 the tubing of the pouch of solution contained in the sealed housing must pass through the wall by means of a joint or stuffing box subjected to the internal pressure. The sealing of the casing, the deterioration of the joint and the problems inherent in the passage of the tubing are a handicap. PA1 1. the envelope of the bag containing the pressure balloon which serves as a pressure reserve is provided with a sleeve of unstretchable material, fixed on two opposite edges of the envelope, the upper and lower ends remaining free and thus constituting a sleeve in which can be inserted a flexible pouch of injectable product which is thus compressed between the envelope and the folded over portion. PA1 The pressure balloon contained within the envelope of this bag can be inflated to a high pressure to ensure the pressure necessary for lifesaving purposes, the pressure being maintained manually or otherwise, during the perfusion without passing through the pressure regulator. This pressure can be 500 millibars or more. PA1 2. The transfusion and perfusion device thus comprises two envelopes each provided with a sleeve. A single one of the envelopes has its pressure regulated for slow perfusion. The other is adapted for rapid perfusion or transfusion in an emergency.
In the third world countries in which the provision of gas cartridges and servicing are chancy, a manual procedure must be found which is better adapted to the practices of the medical profession.
The profusion device for perfusion bags is an improvement on the patent EP 0 351 344 and on French patent 2.631.242, whose capacities it particularly increases.
The device according to the invention permits exerting a sufficient pressure, manually or otherwise, on a flexible pouch of blood or solution to permit a rapid emergency medical or surgical intervention.
The most widespread present practices use suspended pouches but the pressure exerted by atmospheric pressure is often insufficient to ensure the necessary flow rate in major circulatory emergencies, several other processes have been proposed, over which the device of the present invention has numerous advantages.
The slow perfusion device disclosed in the patents cited above ensures a continuous and automatic perfusion for several hours at the same flow rate by establishing a pressure of 100 millibars thanks to two pressure bags communicating by means of a pressure reducer which ensures to a pressure balloon a constant and suitable pressure.
This perfusion device uses the following principle: a reservoir of energy using a compressible and expansible fluid, stores a potential energy sufficient to deliver, as needed, by means of a calibrated expansion valve, a constant and sufficient pressure to a flexible bag of blood or solution and thereby to impose on it normal conditions of all conventional medical perfusions, for a predetermined period of time, without other intervention or reliance on gravity.
This pressure is established in the first bag and regulated to 100 millibars in the second bag. This constant pressure of 100 millibars, if completely suitable for slow and continuous perfusion for several hours, without intervention, does not have a sufficient flow rate to respond to emergencies and hemorrhage or cardiovascular accidents.
To ensure this flow rate and an immediate perfusion, a high pressure is necessary.
The perfusion device which is the object of this new application permits overcoming this drawbacks.